I grow in my shed, affectionately called the “Growage”.
It started out as a 9’ x 16’ interior, I added a 4’ extension to one side, removed the roll up door and framed it in. Put a new roof on.
Insulated under 3/4" floor, walls and ceiling. That addition is where I have my two tents, a 4x4 with extension on taller side and a 3x3 next to it. Between them are my two 12 gallon reservoirs.
I hung blackout curtains in front of the tents, occasionally I’ll run auto’s in front of my tool box. 24 hours on.
I bought a larger window ac unit, cut a hole in the wall. Nice size dehumidifier when needed. In the coldest parts of winter I exhaust back inside. With all LED now I’m finding the 3x3 runs cool with a 300w unit. Next winter a MH/HPS air-cooled hood will most likely go back in. These heat the space much easier. I also have a few 1500w oil filled radiator heaters.
I just started rearranging things, got rid of some tools as I’m now retired and ordered a third tent.
I also have a 4x2x40" tall seedling and cloning cabinet in there. As well as an old foldable camper table and office chair, mini fridge and TV.
It could take some time to dial in but you’ll eventually find a way to make it work. I had no choice… Get to work, and enjoy the rewards.